I have an external monitor and want my macbook screen to go blank or black so I can focus on the monitor instead. On my windows machine Function F5 does this.
Hold down the decrease screen brightness button at the top of the keyboard, it will get dimmer and dimmer, and at the end jump to a black screen (the screen's light will actually be off). To turn the screen back just press the increase screen brightness button.
1This do not turn off the screen but only remove luminosity. The graphic card still have to compute the image and this may slow down your computer unnecessary as you don't use the second screen.– gagarineMar 29, 2021 at 16:53
Turn on your MacBook without the external display connected.
Close the lid and it will go to sleep.
Connect your external monitor and an external keyboard via USB.
Now wake it up by typing on the external keyboard. If you don't have a USB keyboard (you might be using a BT keyboard and mouse) you can use the Apple Remote to wake up a MacBook when its lid is closed.
The MacBook should wake up with the external monitor as its one and only monitor.
4Sounds like he still wants the lid up though? Jun 10, 2011 at 16:04
1Bluetooth mouse/keyboard can wake too.– mspasovJun 10, 2011 at 21:48
1@mindless Once the computer wakes, you can open the lid back up and the display is still off Jun 12, 2011 at 14:45
Kyle, how do you go from that state to re-enabling the main display? Jun 13, 2011 at 18:44
@mindless Go into System Preferences -> Displays and click "Detect Displays" Jun 14, 2011 at 0:50
There doesn't seem to be an out-of-box way to do it in Mac OS, but with this third-party plugin https://github.com/Eun/DisableMonitor does the trick! Just download and run the app form the button in the readme shown, and an icon will show in the menu bar like just like Airplay does, and from it you pick the monitor or monitors shown and whether the Disable it.
1Answers on Ask Different need to be more than just a link. It's okay to include a link, but please summarize or excerpt it in the answer. The idea is to make the answer stand alone.– nohillside ♦Sep 29, 2014 at 13:31